Sturgeon Manual.Pdf
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Manual on Sturgeon Reproduction R Table of Contents I. Introduction..........................................................................................................................3 Biology..................................................................................................................................4 General morphology............................................................................................................4 Geography............................................................................................................................5 Habitat and natural feeding ...............................................................................................5 Sturgeon species ..................................................................................................................6 Production ............................................................................................................................8 Commercial products ...........................................................................................................9 II. Aquaculture and reproduction .........................................................................................11 Hatchery .............................................................................................................................11 Male and female spawners...............................................................................................13 Broodstock raised in captivity ...........................................................................................13 Feeding and feed quality ..................................................................................................14 Handling .............................................................................................................................15 Anaesthetics .......................................................................................................................16 Broodstock selection..........................................................................................................18 Hormonal injection ............................................................................................................21 Semen collection ................................................................................................................22 Female egg collection........................................................................................................24 After care of broodstock and equipment ........................................................................26 Artificial fertilization and egg incubation .......................................................................27 Larval rearing .....................................................................................................................29 First feeding with Artemia nauplii....................................................................................30 First dry feeding .................................................................................................................30 Health management..........................................................................................................31 Hygiene and disinfection...................................................................................................31 Grading...............................................................................................................................32 Feed and feeding ...............................................................................................................33 The future of feeding ........................................................................................................33 References ...............................................................................................................................34 Acknowledgement..................................................................................................................35 Notes........................................................................................................................................36 Appendix .................................................................................................................................38 2 I. Introduction In the 1800s, sturgeon often became entangled in commercial fishing nets, and the fish were discarded as a worthless nuisance. Today, the sturgeon is recognized as one of the world’s most precious commercial fish, mainly prized for its caviar, but increasingly also for its meat and as an ornamental fish. Many sturgeon species are threatened with extinction. Aquaculture, including growing, nurs- ing and reproduction, offers the solution for a sustainable sturgeon production. Furthermore, sturgeon culture is also considered as a business commodity with great economic potential. The first trials in sturgeon farming were already carried out in the mid 19th century, however, sturgeon culture has undergone great development and advances during the last decades. Nowadays, some sturgeon species are already successfully being reproduced and raised in captivity. Figure 1. Unlike their reputation as slow growers in the wild, several species have proven to have very high growth and survival rates and to be tolerant of extremely high stocking densities in culture situations. However, there are also several challenges to the production of sturgeon. Supplies of broodstock and fry are limited. There is a long maturation period before females 3 produce ripe eggs for reproduction. Sturgeon require moderate temperatures for ideal growth and an ample supply of well water. Building facilities for sturgeon production requires high amounts of investment and operating capital. Nevertheless, it is expected that the significance of sturgeon culture will continue to rapidly grow in the coming decade. The basis of every fish farming operation is successful reproduction and the security of a regular supply of high quality fingerlings. Therefore, Coppens International offers this manual to assist in the set up of reliable hatchery procedures for sturgeon. This booklet contains a general description of the sturgeon biology and describes relevant items for successful repro- duction and hatchery management as known for sturgeon at present. It has to be noticed that the described procedures are only meant as guidelines. All mentioned parameters need to be checked and adjusted by the hatchery manager to the specific sturgeon species, life stage and the particular hatchery conditions. Apart from proper management, feed quality is a prerequisite for successful reproduction. SteCo is the Coppens International sturgeon feed range that is especially developed for this species and tested at the Coppens Research Centre (CRC). All Coppens International feeds are kept up-to-date according to the latest technologies and scientific knowledge. Further- more, Coppens International works in close cooperation with its customers. The result of this combined action ensures that optimum feed quality is reached and that excellent growth is achieved. In this way Coppens International contributes to the maximum economic results for the farmers. Biology Sturgeon are one of the oldest groups of living vertebrates and are often described as “living fossils”, with records dating back more than 150 million years. Although life-history traits vary among species, Acipenseriformes are generally long-lived fishes with a slow growth and maturation rate. Some species (e.g., Huso huso) can live for 100 years and exceed 2,000 kg in mass. Such specimens are no longer found but fish over 100 kg are still caught. General morphology Sturgeon skeletons are mostly cartilaginous (like sharks). They have spindle-shaped bodies, snouts with sensory barbells and heterocercal or top-elongated tail fins. They do not have scales, but five rows of large, bony plates called scutes on their back and sides. Paddlefish lack scales and scutes and have a large extended rostrum. 4 Figure 2. Major morphological characteristics of sturgeon and paddlefish. Geography Sturgeon populations are found primarily in cold and temperate regions of the Northern hemisphere, i.e., in North America, Europe and Asia. A few species are found in the rivers on the east and west coasts of Canada and the United States, and in the Mississippi River drainage basin. Other species occur in rivers of Europe, particularly rivers that empty into the Atlantic Ocean, the Adriatic Sea and the Baltic Sea. The most important species of sturgeon are found in the region bordering the Black Sea, the Sea of Azov, the Caspian Sea and the Aral Sea. Sturgeon are also found in watersheds of Asia in rivers emptying into the Sea of Okhotsk, the Bering Sea, the Barents Sea, The Kara Sea and the White Sea. Habitat and natural feeding Acipenseriformes inhabit rivers, estuaries, near-shore oceanic environments and inland seas. Some sturgeon species spend their entire life in freshwater (potamodromous). However, the majority of them are anadromous; they spend their adult life in the sea but swim upriver to freshwater spawning grounds in order to reproduce. They spawn in habitats with hard sub- strates (e.g. gravel, cobbles, boulders) with varying depths and water currents. 5 Most sturgeon species are bottom dwellers and feed benthically on insect larvae, small fish and occasionally on fish-related carrion. In rivers that support salmon popula- tions, sturgeon will forage